Investigation of variations in trend analysis in Southeastern Anatolia region precipitation with different methods

People living in the world have tried to cope with drought and drinking water problems for many years. As a result of the high evaporation rate in the summer months in the Southeastern Anatolia Region of Turkey, depending on the continental climate factor, the need for water storage structures has gained great importance with the effect of global warming over time. The Southeastern Anatolia Region, chosen as the study area, plays an active role in the cultivation of wheat, barley, cotton, red lentils and pistachios. For this reason, dams were built on the Euphrates and Tigris rivers within the scope of the GAP (Southeast Anatolia Project) for various purposes in order to increase agricultural irrigation activities in the region. The GAP project is a project that covers the provinces of the region in order to increase the quality of life in every aspect and includes a series of services aimed at facilitating the lives of the people of the region. In addition, studies have been carried out to strengthen the infrastructure in urban and rural areas. These studies, which were carried out to increase the quality of life of the people of the region, were not only limited to water, but were also carried out in areas such as health, transportation, education and industry. In this study, the data of the rainfall measurement stations between 1970 and 2020 obtained from the Regional Directorate of Meteorology in the provinces of Gaziantep, Sanliurfa, Adiyaman, Kilis, Batman, Diyarbakir, Mardin and Siirt in the Southeastern Anatolia Region were used. Mann-Kendall and Sen trend analysis methods were used through statistical calculation programs to determine the precipitation distribution and trend in the study area. Daily precipitation data at these precipitation observation stations were processed and converted into monthly data and trend analysis was performed. No trends were found in the annual and seasonal analyzes using the Mann-Kendall trend test. In the annual and seasonal analyzes made using the innovative Sen trend analysis method, the presence of a trend was determined. According to the annual total precipitation data in the Sen trend test, an increasing trend was observed in the provinces of Adiyaman, Gaziantep and Siirt in the Southeastern Anatolia Region, and a decreasing trend was observed in Batman, Diyarbakir, Kilis, Mardin and Sanliurfa. In addition, it has been determined that there are increasing and decreasing trends in seasonal total precipitation in the provinces of the region. This situation reveals that innovative trend analysis is a statistically stronger test for trend presence calculation. It has been determined that the distribution of precipitation in the region intensifies in winter and is at the lowest level in summer compared to other seasons. Keywords: Southeastern Anatolia Region, Precipitation, Mann-Kendall Test, Sen Test, Trend Analysis